In the 02 year we plan to conduct additional cryogenic testing of the SMPG in conjunction with dosimetry and radiobiology studies. The computer controlled momentum defining slit system will be completed. Software and electronics will be developed for automating control of the positioning device in conjunction with control of the momentum defining slits. This will allow measurements of simulated simple hypothetical treatment planning calculations. Goals of the dosimetry program during the 02 year include (a) continued measurements of dose distributions with increasing pion energies and various pion beam combinations, (b) continued development of the 60 pion beam monitoring system to include redesign of the ionization chambers and compatible electronics for greater reliability, (c) continued measurements of LET distributions, (d) continued development of passive particle detectors and (e) continued evaluation of the potential of positron ring cameras and multi-wire proportional chambers for pion star imaging as a method of verifying treatment planning calculations. During the 02 year considerable effort will be devoted to determining the RBE and OER of the SMPG pion beams using a cylindrical irradiation device. A gel system will be used to verify treatment planning calculations initially for simple and later for complex dose distributions. This will include the irradiation of irregular volumes and phantoms incorporating simulated tissue inhomogeneity. In the 02 year we will continue treatment planning for hypothetical tumors in all parts of the body using both the biologically equivalent dose and iso-cell survival calculations. Treatment plans of gradually increasing complexity will be performed to evaluate the great potential of treating irregular tumor volumes with the SMPG. BIBLIOGRAPHIC REFERENCES: Boyd, D.P., Fessenden, P., Pistenma, D.A., Schwettman, H.A., Taber, R.: Performance of a Superconducting Multiple-Beam Pion Channel for Cancer Therapy. Presented at the 1975 Particle Accelerator Conference of the American Physical Society March 12-14, 1975.